Acquiring perfect buoyancy


Following straight on from last month's The 5 Essentials, SIMON PRIDMORE describes some useful techniques for improving your buoyancy control.

IN MY PREVIOUS ARTICLE in this series, I discussed a number of essential techniques that all divers should master. One of these techniques was buoyancy control, and I promised to follow up with some advice on how to improve your buoyancy skills.

Perfect buoyancy is a holy grail for many divers. It represents a quest for a nirvana where they will eventually attain the gift of remaining completely motionless in the ocean in any position.

They will become passive observers of the marine world, relaxed and effortlessly neutral. No longer will they be constantly inflating, deflating, rocking and rolling. No longer will they be harbingers of doom for the sea-life around them.

Here are five tips to help you on your own journey to neutral nirvana.


The number one reason why many people find it difficult to control their buoyancy is that they dive over-weighted, and have to compensate for this by adding unnecessary air to their BC in order to stay neutrally buoyant.

Not only does this excess air expand or contract inside your BC’s air-cell with every change in depth, but it also moves around as you change position in the water, making it very hard for you to keep your balance and stay still.

If you reduce the amount of weight you wear, you also reduce the amount of air shuttling about in your BC.
How do you know if you’re carrying too much weight? At the end of a dive, when you have 50 bar or so in your cylinder, position yourself at safety-stop depth, 3m to 5m, remove all the air from your BC and try to remain neutrally buoyant. If you find yourself sinking, you’re wearing too much weight.

If you find yourself tending to float to the surface, then you don’t have enough weight. Easy!

As a general rule of thumb, if you’re still using the same amount of weight you used when you first learned to dive, then there is a good chance that you are diving over-weighted now.

This is partly because as you become more experienced your anxiety levels drop, you relax more, your breathing rate slows and you are able to exhale more fully when you descend.

(Another reason is that dive-instructors tend to overweight new student divers to make them easier to control!)


“But,” you may say, “I can’t take off any weight. I need every bit I carry to get me down at the start of a dive!”

This is probably not true. It is more likely that you’re not getting yourself in the right position and frame of mind before you make your descent.

Point your legs straight down, keep your head up and lift your left arm up holding your inflator hose, index finger poised over the deflate button.

Relax. Take your time. Get your breathing right: long, slow breaths in and long, slow breaths out. Then, after a full inhalation, exhale slowly and completely while pressing the deflate button. And down you go.
Just as in every sport, the way you start is very important, and sets the tone for the rest of the endeavour.

Think of sprinters settling into their blocks or swimmers and (high) divers positioning themselves on their platforms.

Once you are at depth and swimming, add just enough air to your BC to compensate for the compression and reduced buoyancy of your wetsuit and to keep you at the required depth.

Your position in the water should be horizontal. Your fins should be behind you rather than below you, propelling you forward and laterally, creating as little water resistance or drag as possible. A horizontal posture also facilitates the maintenance of perfect buoyancy.

If you are wearing too much weight, it will be impossible to remain horizontal, as the weight around your waist carries your legs downwards while the excess air in your BC settles around your shoulders and lifts your head up.

This may happen even if you’re correctly weighted, as a belt that fits perfectly around your waist at the surface will slip down onto your hips during your descent when your wetsuit becomes compressed.
Make it a habit to hitch up your belt and re-tighten it around your waist once you’re at depth. And, of course, loosen it a little when it gets too tight on the way back up.

If you are naturally floaty or dive in cooler water and wear lots of neoprene, you may have a lot of weight attached to your weightbelt. This not only affects your ability to swim horizontally and efficiently but is also a safety hazard, as you could be at risk of an uncontrollable runaway ascent if it ever slipped off.

A BC with integral weight-pouches on the harness might be the solution, but make sure these are fixed securely and don’t flop away from the body when you are swimming, as this could destabilise you. Also, think about spreading the weight around a little. Put a couple of kilos in pouches on your cylinder camband. This should help bring your feet up and head down.

Remember not to put too much weight in places where it can’t easily be dumped in an emergency. A BC can get punctured, torn or worn, and if that happens it won’t hold air, and you’ll need to be able to drop weight to stay afloat on the surface.


While you are under water, move your fins only when you need to go somewhere. If you’re not going anywhere, keep them still.

You may think you do this already, but the chances are you don’t. Many divers are unaware that they flap continuously and often pointlessly, particularly when they are stressed or distracted. This unconscious activity interferes with your efforts to attain perfect buoyancy.

Keeping your legs and fins from flapping takes a little work. In a pool or a shallow patch of ocean, practise remaining completely motionless in mid-water. If you find yourself slowly being turned in unplanned ways, roll with it.
See where the water takes you. Then turn your body gradually until you’re back on equilibrium by dipping a shoulder, or using breath control to make yourself more or less buoyant.

Breathe in a little more fully to increase your positive buoyancy. Breathe out for a little longer to make yourself more negative. Use your fins only to balance. You may feel an almost uncontrollable urge to kick. Resist it!

Keep your arms tucked in and hands still too. They are of no help in controlling buoyancy under water. Quite the opposite: they are destabilising devices. The best way to throw yourself completely off kilter on a dive is to wave your arms around.

The closer your arms are to your body, the easier it is to maintain perfect buoyancy and balance.
This is why many experienced divers swim with their arms crossed across the chest or hands clasped together.


Most people wear BCs that are too big for them, mainly because they try them on in a shop while they are standing up.

The fit of the harness around your arms and shoulders should be comfortable and allow plenty of movement, but see that it isn’t too loose.

Put it on; do up all the buckles and Velcro, then get someone to lift up the shoulder straps. If their hands hover around your ears when they do that, then that is where the BC will go when you inflate it at the surface after your dive.

A BC is something you should definitely try out in the water before you buy, and the smart dive-shops know this.

Pick the size you think fits you best, and take the next size smaller too. Dive with both of them. The smaller one is probably the one you’ll keep.

Avoid anything bulky and padded. If you’re wearing a wetsuit, padding is unnecessary. Padding also floats.

The greater a BC’s integral buoyancy – that is, the more positive buoyancy it has even when completely deflated – the more extra weight you will have to carry to get it under the water with you.

Your quest for perfect buoyancy requires you to wear less weight, rather than more. So minimal integral buoyancy is a largely ignored but very important feature to look for in a BC.


Once you are weighted correctly, you will need to make only minor adjustments to your BC from time to time during a dive to stay neutral, primarily to compensate for the effect of changing depth and pressure on your wetsuit. To do this, you need to know how your BC works.

Spend time studying it. Know where the controls are. Hold it up in front of you, turn it around and imagine where the air will sit in the BC when you are under water. Be aware that it will always go to whichever part of the air-cell is closest to the surface.

Work out how you would need to turn your body in various positions so that the air is close to one of the pull-dumps and you can release it. For instance, roll your right shoulder down so that your left shoulder is uppermost, and you can raise the inflator-hose and release air.

Or dip your head, raise your butt towards the surface and use the “tail dump”. Practise using your BC in a variety of situations until operating it becomes instinctive.

Perfect buoyancy is within your grasp!

Read more from Simon Pridmore in:
Scuba Confidential – An Insider’s Guide to Becoming a Better Diver
Scuba Professional – Insights into Sport Diver Training & Operations
Scuba Fundamentals – Start Diving the Right Way

All are available on Amazon in a variety of formats.


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